www.nature.com/scientificreports
OPEN
received: 26 February 2015 accepted: 11 August 2015 Published: 18 September 2015
A field experiment with elevated atmospheric CO2-mediated changes to C4 crop-herbivore interactions Haicui Xie1,2, Kaiqiang Liu1, Dandan Sun1, Zhenying Wang1, Xin Lu3 & Kanglai He1 The effects of elevated CO2 (E-CO2) on maize and Asian corn borer (ACB), Ostrinia furnacalis, in opentop chambers were studied. The plants were infested with ACB and exposed to ambient and elevated (550 and 750 μl/l) CO2. E-CO2 increased the plant height and kernel number per ear. The plants had lower nitrogen contents and higher TNC: N ratios under E-CO2 than at ambient CO2. The response of plant height to E-CO2 was significantly dampened in plants with ACB infestation. However, the weight gain of the survivors declined in plants grown under E-CO2. Moreover, the plant damage caused by ACB was not different among the treatments. Overwintering larvae developed under E-CO2 had a lower supercooling point than those developed under ambient CO2. The results indicated that there was a positive effect of E-CO2 on the accumulation of maize biomass, i.e., the “air-fertilizer” effect, which led to a nutritional deficiency in the plants. The fitness-related parameters of ACB were adversely affected by the CO2-mediated decreased in plant nutritional quality, and ACB might alter its food consumption to compensate for these changes. Larval damage to maize under E-CO2 appears to be offset by this “air-fertilizer” effect, with reductions in larval fitness.
Since the Industrial Revolution, the huge consumption of fossil fuels and the destruction of natural habitats by the activities of humans have led to a continuous increase in CO2 concentrations in recent decades. The ambient CO2 concentration is expected to double within the 21st century, i.e., it will increase from the current level of ∼ 379 μ l/l to 700 μ l/l1. Because of the “fertilization effect”2, most C3 plants increase the rates of photosynthesis and photosynthate production when exposed to elevated CO2 (E-CO2)3. The phenotype response of plants to E-CO2 is generally an increased rate of growth and biomass accumulation4,5. However, not all plant species respond identically to E-CO2. Exposure to E-CO2 increased the biomass of Agrostis capillaris (L.) and Poa alpine (L.), but the biomass decreased in Festuca vivipara (L.)6. Additionally, the responses of plants may be different in the short term compared with the long term. The biomass of alfalfa, Medicago sativa (L.), and orchard grass, Dactylis glomerata (L.), was unaffected in the final two years of a 3-year experiment7. From the fertilization effect caused by the E-CO2, the increased rate of photosynthesis increases plant metabolism and generates plants with higher carbon-to-nitrogen ratios (C: N)8. Simultaneously, E-CO2 can lead to changes in plant secondary metabolism because of alterations in the plant allocation to defence chemistry and chemical signalling9. The concentrations of phenolics, terpenoids, condensed tannins, and gossypol were higher in Bt cotton, Gossypium hirsutum (L.), plants grown under E-CO2, but the concentration of the Bt toxin protein decreased10. In soybean, Glycine max (L.), plants grown under 1
The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. China. 2College of Life Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066000, P. R. China. 3Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, P. R. China. Correspondence and requests for materials should be addressed to K.H. (email: [email protected]) Scientific Reports | 5:13923 | DOI: 10.1038/srep13923
1
www.nature.com/scientificreports/ CO2 levels
Water
N
Soluble sugar
Starch
Organs
(μl/l)
(%)
(%)
(mg/g)
(mg/g)
TNC: N
Leaves
Ambient
76.86 ± 2.25
3.26 ± 0.08a
27.94 ± 0.61a
118.74 ± 0.89a
4.49 ± 0.07a
550
76.17 ± 1.67
3.14 ± 0.04a
29.94 ± 1.46ab
122.93 ± 1.89ab
4.87 ± 0.07b
750
73.67 ± 1.96
3.00 ± 0.04b
32.34 ± 0.47b
128.61 ± 1.29b
5.32 ± 0.02c
F2,6
0.69
5.33
7.98
4.93
58.85
Stalks
P
0.54
0.04
0.02
OPEN
received: 26 February 2015 accepted: 11 August 2015 Published: 18 September 2015
A field experiment with elevated atmospheric CO2-mediated changes to C4 crop-herbivore interactions Haicui Xie1,2, Kaiqiang Liu1, Dandan Sun1, Zhenying Wang1, Xin Lu3 & Kanglai He1 The effects of elevated CO2 (E-CO2) on maize and Asian corn borer (ACB), Ostrinia furnacalis, in opentop chambers were studied. The plants were infested with ACB and exposed to ambient and elevated (550 and 750 μl/l) CO2. E-CO2 increased the plant height and kernel number per ear. The plants had lower nitrogen contents and higher TNC: N ratios under E-CO2 than at ambient CO2. The response of plant height to E-CO2 was significantly dampened in plants with ACB infestation. However, the weight gain of the survivors declined in plants grown under E-CO2. Moreover, the plant damage caused by ACB was not different among the treatments. Overwintering larvae developed under E-CO2 had a lower supercooling point than those developed under ambient CO2. The results indicated that there was a positive effect of E-CO2 on the accumulation of maize biomass, i.e., the “air-fertilizer” effect, which led to a nutritional deficiency in the plants. The fitness-related parameters of ACB were adversely affected by the CO2-mediated decreased in plant nutritional quality, and ACB might alter its food consumption to compensate for these changes. Larval damage to maize under E-CO2 appears to be offset by this “air-fertilizer” effect, with reductions in larval fitness.
Since the Industrial Revolution, the huge consumption of fossil fuels and the destruction of natural habitats by the activities of humans have led to a continuous increase in CO2 concentrations in recent decades. The ambient CO2 concentration is expected to double within the 21st century, i.e., it will increase from the current level of ∼ 379 μ l/l to 700 μ l/l1. Because of the “fertilization effect”2, most C3 plants increase the rates of photosynthesis and photosynthate production when exposed to elevated CO2 (E-CO2)3. The phenotype response of plants to E-CO2 is generally an increased rate of growth and biomass accumulation4,5. However, not all plant species respond identically to E-CO2. Exposure to E-CO2 increased the biomass of Agrostis capillaris (L.) and Poa alpine (L.), but the biomass decreased in Festuca vivipara (L.)6. Additionally, the responses of plants may be different in the short term compared with the long term. The biomass of alfalfa, Medicago sativa (L.), and orchard grass, Dactylis glomerata (L.), was unaffected in the final two years of a 3-year experiment7. From the fertilization effect caused by the E-CO2, the increased rate of photosynthesis increases plant metabolism and generates plants with higher carbon-to-nitrogen ratios (C: N)8. Simultaneously, E-CO2 can lead to changes in plant secondary metabolism because of alterations in the plant allocation to defence chemistry and chemical signalling9. The concentrations of phenolics, terpenoids, condensed tannins, and gossypol were higher in Bt cotton, Gossypium hirsutum (L.), plants grown under E-CO2, but the concentration of the Bt toxin protein decreased10. In soybean, Glycine max (L.), plants grown under 1
The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. China. 2College of Life Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066000, P. R. China. 3Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, P. R. China. Correspondence and requests for materials should be addressed to K.H. (email: [email protected]) Scientific Reports | 5:13923 | DOI: 10.1038/srep13923
1
www.nature.com/scientificreports/ CO2 levels
Water
N
Soluble sugar
Starch
Organs
(μl/l)
(%)
(%)
(mg/g)
(mg/g)
TNC: N
Leaves
Ambient
76.86 ± 2.25
3.26 ± 0.08a
27.94 ± 0.61a
118.74 ± 0.89a
4.49 ± 0.07a
550
76.17 ± 1.67
3.14 ± 0.04a
29.94 ± 1.46ab
122.93 ± 1.89ab
4.87 ± 0.07b
750
73.67 ± 1.96
3.00 ± 0.04b
32.34 ± 0.47b
128.61 ± 1.29b
5.32 ± 0.02c
F2,6
0.69
5.33
7.98
4.93
58.85
Stalks
P
0.54
0.04
0.02
